The teeth and jaws are the substructure for the lower two-thirds of the face. Orthodontists, oral surgeons and plastic surgeons often change the position of the teeth and jaws and, as a result, the soft tissues of the lower two-thirds of the face. Currently these specialists are using dental casts mounted on conventional articulators to show: the distance the maxillary (upper) teeth are from the temporomandibular joints (TMJs), the superior/inferior (above/below) position of the teeth relative to a third reference point, and how the teeth relate to each other. The third reference point is typically an internal reference point on the skull, such as the inferior border of the orbit (the bottom of the eye socket). In that conventional articulators do not simulate any portion of the patient's face or how the teeth relate to the face, photographs from the front and sides of the face as well as lateral radiographs of the head are used to show the relationship of the teeth to the face, to learn the extent that teeth and jaws can contribute to or detract from the harmony of the face, and to plan changes needed for full facial harmony.
Conventional dental articulators consist essentially of a one part upper member and a one part lower member coupled together by a joint which simulates the TMJs. The upper member of the articulator simulates a transverse section of the cranial base to which maxillary (upper jaw) casts can be mounted using plaster and a mounting plate. The lower member of the articulator simulates the mandible (lower jaw) to which mandibular casts can be mounted, also using plaster and a mounting plate. The mounting plates are commonly secured to the upper and lower members of the articulator using screws. Auxiliary devices, such as facebows with waxed bite forks, are used to record the anterior/posterior (A/P) distance the maxillary arch is from the TMJs, and the superior/inferior S/I) position of the maxillary arch relative to a third reference point on the skull such as the inferior border of the orbit. The thin wafer of wax is used to record the orientation of the mandibular arch to the maxillary arch. These same auxiliary devices and materials are used to orient dental casts to the articulator. The casts are then secured to the articulator using mounting plates and plaster. This permits the dental casts to be oriented to the articulator's TMJs, to a third reference point, and to each other just as the teeth are oriented to these anatomical structures and to each other on a patient. However, there is no way to know with conventional articulators alone how the teeth relate to the face or to their A/P treatment goal position.